"I did NOT know of the meeting with my son, Don jr", Trump wrote in on Twitter after a CNN report cited his longtime lawyer Michael Cohen as saying Trump had known about the meeting in advance.
CNN cited anonymous sources saying Cohen was willing to share his information with Mueller, who is investigating possible collusion between Trump's campaign and Russian Federation.
Rudy Giuliani told Laura Ingraham it was "outrageous" for Cohen to tape his client surreptitiously and "foolhardy for them to try to yell and scream and make believe what's on the tape".
Nunberg said on NBC's "Meet the Press" that it was common knowledge among Trump's associates that Cohen recorded phone calls.
Cohen is under criminal investigation in the Southern District of NY because of his business dealings and efforts during the 2016 campaign to suppress negative stories about Trump.
Per Giuliani, Trump and other participants in that alleged meeting claim it did not occur, and that Cohen has provided different dates for the discussion.
"We've indicated to them that they should respect the client and attorney privilege in different ways", Giuliani said on ABC. "Do you think the Fake News Media will ever report on this tweet from Michael?" the president questioned. I didn't know that.
The recording between Cohen and Mr. Trump was aired by CNN last week. After giving ever-shifting explanations, Trump Jr. eventually admitted that he talked to the Russian lawyer Veselnitskaya after being promised some dirt on Hillary Clinton.
Giuliani also said that Cohen has been described as a "pathological liar".
Donald Trump Jr. told investigators from the Senate Judiciary Committee in September 2017 that he did not tell his father about the meeting beforehand, according to documents released by the committee.
Nunberg said that the conversation, released last week by CNN, sounded "like the conversations you would hear in private" in Trump Tower.
Trump Jr. testified previous year to the Senate Judiciary Committee that his father had no knowledge of the meeting with the Russians.
"Look, they're obviously trying to undermine Cohen's credibility", Abrams said.
Trump complained that he had returned from a trip Midwest Thursday "only to be greeted with the ridiculous news" that Mueller and his team "cannot find Collusion... so now they are looking at my Tweets (along with 53 million other people)".